Ford 83-94 6.9 and 7.3L General Discussion of 83-94 6.9 and 7.3 Liter Ford Diesels

1990 7.3 miss

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  #1  
Old 06-20-2010, 10:07 AM
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help 1990 7.3 miss

this is what i got.. just rebuilt sleeved all cylinders heads rebuilt put it together ran it about 90 miles... it has dual exhaust 12" glasspacks.. on the driver side out of the exhaust tip it sounds like a dead miss. under the hood you cant notice it at all ..injector pump has about 500 miles on it new lift pump, injectors are not new as they seemed fine before rebuild no smoke out of exhaust just the black puff when you rev it up so cracked injector lines and the engine would stumble on all 8 injectors did a compression test through glowplugs on driver side all 4 cylinders were 440-480psi so even with good compression i pulled the valve cover checked rocker arms and springs all were fine even cut the pipe off before the glasspack to see if it was making the exhaust sound different this exhaust noise only started about 5 miles ago with the valve cover off and the engine running it sounds like you can hear exhaust its hard to tell it could just be the springs working any ideas
 
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Old 06-20-2010, 05:26 PM
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you could have gotten a bad valve spring. pain to pull out and test.
 
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Old 06-22-2010, 07:39 PM
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checked compression again driver side first cyl 460 (2)480 (3)460 (4) 520psi and the glowplug was wet the rest were dry when pulled out. could it be a lifter??
 
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Old 06-23-2010, 08:03 PM
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leaning more to a stuck injector now with last info. stuck open and spraying all the time and hitting on exhaust stroke also.
 
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Old 06-23-2010, 08:44 PM
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swaped the injectors from passenger to driver the problem stayed on the driver side no difference at all... there is no excess smoke from either side.. how do you check for a intake leak?? last step before before pulling the head i guess bought new vally pan when putting engine back together but maybe something is up with it
 
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Old 06-24-2010, 08:27 PM
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i use wd-40 and spray around mating surfaces and if it is sucked in at any point you have a leak. i'm surprised noone else has chimed in on this, there are some very knowledgable guys on here. starting to run out of ideas and things to check.
 
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Old 06-25-2010, 07:19 AM
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Yea i'm about out of ideas too
 
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Old 06-26-2010, 08:50 AM
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Default 7.3 miss

have you had a good look at your exhaust manifold for cracks or damaged maniflod gasket and the exhaust donnut where your pipe connects to manifold for loose bolts etc:
 
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Old 06-26-2010, 07:54 PM
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On my 6.9 when i bought it it had a glasspack on it and i also thought it had a miss from listening to it but could never figure it out and it went away when i took it off and straight piped it...but i can't say for sure thats ur problem...just my 2cents good luck man
 
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Old 06-27-2010, 06:20 PM
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i checked the manafod and the gasket for leaks with my hand couldnt feel anything no leaks at donut...... I already cut the pipes off before the glasspack.... no leaks at intake manafold
 


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